| 摘要 |
<p>If the power of a hydraulic motor (23) is insufficient to rotate a rotary (20) to start unscrewing a joint, bolts (26, 27) are advanced to inhibit relative rotation between the rotary (20) and the housing (19). Hydraulic fluid is then directed to cylinders (9, 14) to rotate the housing (19), rotary (20), jaws (21) and pipe sufficient to start unscrewing the joint.</p> |
